Coupling apparatus for pipe

ABSTRACT

This invention relates to a coupling apparatus for pipe, such as a valve, meter riser, tee fitting, or the like. The apparatus is characterized by a body portion having provision therein for the insertion of a length of pipe having a rigid insert positioned therein with an exposed flange extending therefrom, in conjunction with a rigid tubular collar, a compression ring and a tightening nut which is threadably connected to the body portion for the compression of the compression ring against the collar to apply compressive pressure on the pipe in an arrangement such that pull on the pipe is applied to the collar and thence to the compression ring applying increased compression on the ring.

United States Patent 1 1 Riggs et al.

[ COUPLING APPARATUS FOR PIPE Sept. 4, 1973 [75] inventors: Jerry W.Riggs; Roy E. Stiner, both of Tulsa, Primary ExaminerDave W. Arola [73]Assignee: Continental Industries, Tulsa, Okla. A170 James Head and PaulJohnson [22] Filed: Nov. 10, 1971 21 Appl. No.: 197,309 57 ABSTRACT Thisinvention relates to a coupling apparatus for pipe, 8" 2.12? such as avalve, meter riser, tee fitting, or the like. The Fie'ld 334 5 apparatusis characterized by a body portion having 5 provision therein for theinsertion of a length of pipe having a rigid insert positioned thereinwith an exposed 56] References Cited flange extending therefrom, inconjunction with a rigid tubular collar, a compression ring and atightening nut UNITED STATES PATENTS which is threadably connected tothe body portion for 2,300,584 ll/l942 Martin 285/356 X the compressionof the compression ring against the 21950928 8/1960 Bowa" 285/38 Xcollar to apply compressive pressure on the pipe in an naught Xarrangement such that pull on the pipe is applied to the 67258 7x939 ET;238 collar and thence to the compression ring applying increasedcompression on the ring FOREIGN PATENTS OR APPLICATIONS I 218,472 3/1958Australia 285/250 1 Claim, 3 Drawing Figures /0 /2 34 32 /8 -22 40:/6B24 27 l8/l i /6 3 8 l T 1 36A l i 3 0 28A 26 28 36 i3 5. 27A

COUPLING APPARATUS FOR PIPE SUMMARY OF THE INVENTION Coupling apparatusare widely utilized in the gas and water industry. One form of couplingapparatus is that required to provide a connection of a length of pipe,for example, polyethylene or polyvinylchloride plastic pipe or metalpipe, with a metallic member, such as a valve, meter riser, tee fitting,a length of metal pipe, or the like.

A common problem with connectors of this type is that of gripping thepipe sufficiently to prevent it from being pulled out of the connector.This invention provides an improved means of gripping pipe in aconnector, and most significantly, an improved means of increasing thegripping force in proportion to the amount of pull exerted on the pipe.

OBJECTS OF THE INVENTION A basic object of this invention is to providean improved coupling for pipe.

A more specific object of the invention is to provide a coupling forattaching pipe to a metal device including means wherein the grippingforce applied to the pipe increases as force is applied to pull the pipeout of the coupling.

These and other objects will be fulfilled in the apparatus set forth inthe following description and claims, taken in conjunction with theattached drawings.

DESCRIPTION OF THE VIEWS FIG. 1 is a side view of an embodiment of thecoupling apparatus of the invention, forming, as an example, a portionof a tee fitting, the coupling being used to attach a length of pipe.

FIG. 2 is a partial cross-sectional view of the tee fitting of FIG. 1,showing the coupling apparatus of this invention in greater detail.

FIG. 3 is a cross-sectional view taken along the line 3-3 of FIG. 2.

DETAILED DESCRIPTION Referring now to the drawings, the couplingapparatus of this invention is indicated generally by the numeral 10.The coupling apparatus includes a body portion 12, which, by way ofexample, is shown to be part of a tee fitting 13, it being understoodthat body portion 12 may be in many different forms. The couplingapparatus may be used to couple metal or plastic pipe and will bedescribed, by way of example, as used to couple plastic pipe. A lengthof plastic pipe 16 extends within body 12 through the bore 18A in atightening nut 18.

Body 12 has a first axial bore 20 extending from one end thereof andcommunicating with the other portions of tee fitting 13. The oppositeend of body 12 has a larger diameter bore 22, coaxial with bore 20. Aportion of the bore 22 is provided with internal threads at 24. Bore 22meets with coaxial bore 20 to form an internal flange surface 26.

Tightening nut 18 includes an integral, reduced diameter tubular portion27 having external threads 27A thereon, which, when the couplingapparatus is assembled, engages body internal threads 24.

Positioned in the end portion of pipe 16 is a rigid insert 28 having anaxial bore 30 therethrough. The outer circumferential surface 32 of theinsert is of a diameter to slidably but snugly fit the interior diameterof pipe 16. In addition, the outer surface 32 of insert 28 is preferablyprovided with serrations 28A to improve the gripping efiect on theinterior of pipe 16.

Insert 28 is flared at the forward end to an outside diameter exceedingthe diameter of pipe 16, the flared portion being indicated by thenumeral 34.

Received about pipe 16 within the bore 22 is a collar member 36. Theoutside diameter of collar 36 is slightly less than the internaldiameter of bore 22 so that the collar is slidable within bore 22.Collar 36 is less slidable on pipe 16. The forward end 36A of collar 36is provided with an internal circumferential recess 38 which receivesthe insert flared portion 34.

Received on the exterior of pipe 16 within body 12 is a compression ring40 of resilient material. Like collar 36, the outside diameter of thecompression ring 40 is of a dimension to be slidable within bore 22 andthe interior diameter to be slidable upon pipe 16, but with a snug fit.The compression ring is engaged by the collar rearward end 36B on theone hand and the tightening nut forward end 18B on the other. Astightening nut 18 is threadably advanced, compression ring is squeezedagainst collar 36, distorting the compression ring into engagement withthe exterior of pipe 16.

ASSEMBLY AND APPLICATION OF THE DEVICE When the device is to be used toconnect a length of plastic pipe 16 to the tee fitting 13 or any otherobject of which body portion 12 forms a part, the end of the pipe to beconnected first receives nut 18. Next, the

' compression ring 40 is slid upon pipe 16 followed by collar 36. Insert28 then is positioned in the end of the pipe 16 so that the flangeportion 30A is immediately adjacent the end of the pipe.

The end of pipe 16 having insert 28 therein and having collar 36 andcompression ring 40 thereon is inserted into the body bore 22 so thatthe forward end 36A of collar 36 engages the flange surface 26. Thetightening nut tubular portion 27 is inserted into bore 22 and thethreads 27A thereon engages internal threads 24. Tightening nut 18 isthen rotated so that forward end 18A engages compression ring 40.Further rotational advancement of the locking nut compresses thecompression ring against collar 36 .to distort the compression ring intopositive engagement with the exterior of pipe 16. The insert 28 withinpipe l6'prevents it from collapsing so that a positive leakproofengagement is'obtained between the nipple l2 and pipe 16.

An important advantage of the coupling of this invention is theprovision of means wherein as pull is exerted on pipe 16, thecompressive force applied against the pipe by compression ring 40 isincreased. This is accomplished in this manner: as pull is exerted onpipe 16 it is transmitted by way of the flared portion 34 of insert 28to'collar 36 which is slidable within the body and the force exerted onthe collar is directly applied against compression ring 40, increasingthe compressive distortion thereof into increased engagement with pipe16. Thus, the coupling apparatus has a self-energizing compressionfitting responsive to pull exerted on pipe 16. The increased compressiveforce is not applied in such a way as to cut into the pipe or militateagainst the inherent strength of the pipe.

The invention has been described as it is particularly applied when pipe16 is of plastic. The device may be used with other types of pipe, suchas copper, steel, or other metal. When used with metal pipe the insert28 is not required, and instead, the pipe is integrally flared on theend to provide flared portion 34. The coupling functions in the sameself-energizing way to impose increased compressive distortion of thecompression ring 40 as pull is extorted on the pipe. The term pipe"includes tubing and conduit.

While the invention has been described with a certain degree ofparticularity it is manifest that many changes may be made in thedetails of construction and the arrangement of components withoutdeparting from the spirit and scope of this disclosure. It is understoodthat the invention is not limited to the illustrated embodiments setforth herein for purposes of exemplification, but is to be limited onlyby the scope of the attached claim or claims, including the full rangeof equivalency to which each element or step thereof is entitled.

What is claimed:

1. A coupling apparatus for a plastic pipe, comprismg:

a body having a first axial bore in one end of a diameter approximatelythe inside diameter of the pipe, and a second axial bore on the otherend of a diameter greater than the outside diameter of the pipe, thefirst and second axial bores being coaxial and meeting to form aninternal flange;

a rigid insert having an axial bore therethrough, the

outer circumferential surface of which is the approximate diameter ofthe inside diameter of the pipe, the insert being positioned within theend of the pipe, and the insert having a flare end thereon exposed atthe end of the pipe, the pipe having the insert therein being positionedwithin the body second bore so that the flared end of said insert buttswith said internal flange;

rigid tubular collar having an inside diameter approximately the outsidediameter of the pipe and an outside diameter approximately that of thesecond axial bore of the body, the collar being positioned about thepipe within the body second bore, one end of the collar having a recesstherein receiving the flared end of the insert, the collar beingslidable relative to the body and the pipe;

a compression ring of resilient material having an inside and outsidediameter dimensionally similar to said collar and positioned about thepipe within the body second bore, one end of the compression ringabutting the other end of said collar; and

tightening nut having an externally threaded portion received by theinternally threaded second axial bore of said body, the tightening nuthaving an axial bore receiving the pipe, the end of the portion withinsaid body second bore engaging said compression ring whereby tighteningsaid nut within said body causes the compression ring to securely engagethe pipe and whereby pull on the pipe exerts pull on said insert andthereby on to said collar to apply increased compression force on saidcompression ring.

i I I. i t

1. A coupling apparatus for a plastic pipe, comprising: a body having afirst axial bore in one end of a diameter approximately the insidediameter of the pipe, and a second axial bore on the other end of adiameter greater than the outside diameter of the pipe, the first andsecond axial bores being coaxial and meeting to form an internal flange;a rigid insert having an axial bore therethrough, the outercircumferential surface of which is the approximate diameter of theinside diameter of the pipe, the insert being positioned within the endof the pipe, and the insert having a flare end thereon exposed at theend of the pipe, the pipe having the insert therein being positionedwithin the body second bore so that the flared end of said insert buttswith said internal flange; a rigid tubular collar having an insidediameter approximately the outside diameter of the pipe and an outsidediameter approximately that of the second axial bore of the body, thecollar being positioned about the pipe within the body second bore, oneend of the collar having a recess therein receiving the flared end ofthe insert, the collar being slidable relative to the body and the pipe;a compression ring of resilient material having an inside and outsidediameter dimensionally similar to said collar and positioned about thepipe within the body second bore, one end of the compression ringabutting the other end of said collar; and a tightening nut having anexternally threaded portion received by the internally threaded secondaxial bore of said body, the tightening nut having an axial borereceiving the pipe, the end of the portion within said body second boreengaging said compression ring whereby tightening said nut within saidbody causes the compression ring to securely engage the pipe and wherebypull on the pipe exerts pull on said insert and thereby on to saidcollar to apply increased compression force on said compression ring.